"pubdate" does not accept first day of the month from automatic input

[Arturo Orlando]

Calibre 3.38.1 (official download)
Lubuntu 16.04 32-bit (up to date and still supported)

-Steps:

1) Create the following dummy files:
touch Test%Test%2001-01-01.txt
touch Test%Test%2001-06-01.txt
touch Test%Test%2001-01-01T00:00:00.txt
touch Test%Test%2001-06-01T00:00:00.txt
touch Test%Test%2001-01-01T12:00:00.txt
touch Test%Test%2001-06-01T12:00:00.txt
touch Test%Test%2001-01-01T00:00:00Z.txt
touch Test%Test%2001-06-01T00:00:00Z.txt
touch Test%Test%2001-01-01T12:00:00Z.txt
touch Test%Test%2001-06-01T12:00:00Z.txt

2a) Import them into Calibre, reading the metadata from the file name:
(?P<author>[^%]*)%(?P<title>[^%]*)%(?P<published>[^%]*)

2b) Alternatively, read the date of publication as a comment:
(?P<author>[^%]*)%(?P<title>[^%]*)%(?P<comments>[^%]*)

3b) Then, move it to the "pubdate" column through search and replace
(.*)
\1

-Result (in both cases):
The publication date for all books is 2001-01-02 / 2001-06-02.
Changing the system time zone to UTC makes no difference.
Manual input does not trigger the bug; only automatic import does.

[Kovid Goyal (kovid)]

yeah that's to ensure the read date has the correct month in all
timezones, at the cost of being potentialy one day off.

 status wontfix

[Arturo Orlando (arturo-orlando)]

OK. Thank you.